package com.example.forum.interceptor;

import com.example.forum.config.AppConfig;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

@Component
public class LoginInterceptor implements HandlerInterceptor {

    @Value("${bit-forum.login.url}")
    private String url ;
    /**
     * 前置处理/预处理 对请求的预处理
     * @return  true 继续请求流程 <br/>  false 表示流程中断
     * @throws Exception
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        HttpSession session = request.getSession(false);
        if (session != null
                && session.getAttribute(AppConfig.USER_SESSION) != null) {
            return true;
        }
        // 校验不通过 , 用户没有登录
        if (!url.startsWith("/")) {
            url = "/" + url;
        }
        response.sendRedirect(url);
        return false;
    }
}
